1. Field of the Invention
The present invention relates to an arithmetic unit. Mare particularly, the invention relates to an arithmetic unit, a processor, a compiler and a compiling method for performing a floating-point arithmetic operation and an integer arithmetic operation.
2. Description of the Related Art
Real numbers are represented as, for example, integer type (i.e., fixed-point type) data and floating-point type data in an information processing device, such as a computer. In order to change the sign of floating-point type data, a floating-point arithmetic unit dedicated to performing arithmetic operations on floating-point type data has been used. Recently, there is a demand for a device that converts the sign of floating-point type data at higher speed. In order to meet such a demand, an arithmetic unit that performs integer arithmetic operations in which floating-point type data is treated as unsigned integer type data has been proposed (see, for example, FIG. 1 of Japanese Unexamined Patent Application, First Publication No. 2005-31847). The arithmetic unit performs an integer arithmetic operation while treating floating-point type data as unsigned integer type data so that only a sign bit representing the sign of floating-point type data is changed into a bit value which represents a positive number.